With tickets costing around $12 each and concessions costing nearly as much, moviegoers know how pricey it can be to see the latest Hollywood hits. But one Michigan man is tired of spending so much cash at the theater.

Film buff Joshua Thompson, who lives just outside Detroit, used to take his own snacks to the theater in order to save money. But on a recent visit to his nearby AMC Theatre, Thompson saw that the theater had posted a sign telling customers they were no longer allowed to bring in their own popcorn, candy and soda.

“He called me and said, ‘Can they do that?’” Thompson’s attorney Kerry Morgan told the Los Angeles Times. Morgan did some research and found that AMC may be violating the Michigan Consumer Protection Act, which prevents price gouging.

According to Thompson’s lawsuit, on a December trip to the theater, he paid $8 for a Coke and a packet of Goobers—nearly three times what he would have paid at a nearby drugstore. The suit seeks a civil penalty against AMC and refunds for customers.

Some legal experts say movie theaters and other regulated businesses are exempt from the state’s price-gouging statute, but Morgan told the Times that he is “going to test the legal boundaries of that state law.”